There are various engaging devices which move between engaging and release conditions by way of a snap-action process. Typical of such devices is an articulable article which is described and illustrated in GB 1212248 (Westhem) and which is well adapted for use as a clipping or gripping device. The articulated article, when functioning as a gripping device, comprises first and second swingable members movable between closed (engaging) and an open (release) positions. The swingable members are mounted on a resiliently bendable support structure comprising two upright members, the first swingable member being hingedly joined to one of the upright members through a flexible web constituting a first hinge line and the second swingable member being hingedly joined to the other of the upright members through a further flexible web constituting a second hinge line. The first and second swingable members are hingedly joined together through a third hinge line. The resiliently bendable characteristic of the support structure is provided by at least one of the upright members being resiliently bendable so allowing the two swingable members to swing respectively about the first and second hinge lines between the open and closed positions. In moving between the open and closed positions, the swingable members move through an unstable "over-toggling" position in which the three hinge lines are in alignment, and the resiliently bendable support structure deflects outwardly to accommodate this movement. As the support structure deflects outwardly, its resilient nature influences the swingable members and produces the snap-action between the open and closed positions.
Somewhat similar engaging devices are disclosed in U.S. Pat. No. 4,071,930 (Tanaka), U.S. Pat. No. 4,240,604 (Brach) and U.S. Pat. No. 4,514,885 (Delahousse).
A common feature of all of the aforementioned prior art engaging devices is that the swingable members are supported on a support structure which is resiliently bendable to allow the arms to swing through an "over-toggling" position, with the resilient nature of the support structure influencing the swingable members as they move between two stable positions one each side of the unstable "over-toggling" position.
A further common feature of the prior art devices is that they are of one-piece construction with various sections connected together with film hinges. This has disadvantages in certain circumstances. One disadvantage is a limitation in the strength that can be achieved at the film hinges. Another disadvantage is that the support structure interferes which access to the inner side of the swingable members.
While the prior art engaging devices do perform satisfactorily in many situations, there are other situations in with it would be useful to have a snap-action engaging device which does not have a resiliently bendable support structure of the kind used in the aforementioned prior art engaging devices.